Undercoat for lacquers and lacquered material



Patented Jan. 21, 1936 1 h V 2,028 185} 'UNITED STATES PATENT OFFICE UNDEBCOAT FOR LACQUERS AND mcounaizn MATERIAL Walter B. Bowlby, Wilmington, Del., assignor to Hercules Powder Company, Wilmington, Del., a corporation of Delaware No Drawing. Application October 12, 1932, Serial No. 637,552

9 Claims. (Cl. 91-68) This invention relates to an improvement in for the size or undercoating with consideration undercoat for lacquers and in lacquered material. for various applications or uses of the coated ma- Heretofore it has been known to apply a coatterial. 7 ing of lacquer, as nitrocellulose lacquer, to the Generally speaking, a satisfactory size or unsurface of porous papers, carton board and other dercoating may contain starch 2-25%, a softener fibrous or felted fibrous materials, as such or as 0.5-20% and water 97.555%.

' fabricated into various forms, in order to provide As illustrative of the preparation of a size in aca degree of moisture and grease resistance and cordance with this invention, for example, the to give a gloss to the surface. Heretofore, howdry starch is wetted out with cold water and after 10 ever, the coating of lacquer has been applied dicomplete dispersion the mixture is poured slow w rectly to the carton board or other fibrous maly and with constant stirring into the desired terial and the results have not proved entirely amount of boiling water. The starch will become satisfactory, since an excessive quantity of laccompletely dissolved after a brief period and the quer has been required due to the absorptiveness size may then be applied, in any desired manner,

of the material into which the lacquer penetrates, as by spraying, brushing, or the like, or more 5 rendering it difiicult to obtain a desired surface desirably through the medium of a roll by which coating. the starch will be transferred from a container,

Now, in accordance with this invention, it has as a tub or pan, to the surface of the paper been found that an improved lacquer coating may or carton board to be sized or undercoated.

be obtained on materials of the type indicated, Where it be desirable to include in the size as porous paper, carton board, etc., etc., if the maa softener, the softener may, for example, be terial be first sized or undercoated with starch, added to and mixed into the solution of starch which will form, in combination with a given in water. Alternatively, for example, the softamount of lacquer a coating having grease and ener may be added to the cold water with which moisture resistance to a very superior degree and the starch is wetted out and the mixture, includone having a superior gloss. ing the softener, added to boiling water.

In addition to afiording superior grease and As more specifically illustrative of the pracmoisture resistance and superior gloss, the use tical adaptation of is invention, for e p of starch as a size or undercoat in combination satisfactory undercoatings may be made up on 3 with a lacquer will be advantageous in view of the the following formulae:

lig t colored white coating provided by the starch, the fact that starch does not have and will not 2 zl acquire any bad odor and in that the starch coatg g 'g g'gfi" ing or film is not normally objectionably brittle Water and may be readily plasticized to give a coating 35 or film of desired flexibility. The formula above may be made up, as de- In carrying this invention into practice, variscribed, by wetting out the starch with cold water ous types of starchmay be used. Thus, for exand dissolving in boiling water, with final addiample, corn starch, potato starch, wheat starch, tion of the glycerol or sulphonated castor oil, or

40 etc., etc., may be used, and such may be of a comthe softener may be added to the wetting out 40 mercial grade, but in order to keep the amount of water and the mixture dissolved in boiling water, water in the size, as preferred, at a minimum, it or otherwise. will be desirable to use a starch of low viscosity. In making up the size or undercoating when While the size or undercoat, in'accordance with a softener is used, it has been found that glycerol this invention, may consist of starch only, it will is most satisfactory in that it is light colored and 45 be desirable to include a softener or plasticizer free from odor and does not raise the viscosity for the starch, as, for example, glycerol, sulof the solution.

phonated castor oil, mixed esters of carbohy- In combination with the size or undercoating drates, as glucose aceto lactate, etc., etc., in orin accordance with this invention, various nitroder to make the dried starch film more flexible. cellulose lacquers may be used, the particular 50 As has been indicated, the starch may be used lacquer most desirable being selected with conin widely varying amount as may also the softsideration for the use for which the lacqueredener or plasticizer. The relative proportions of material is intended. Thus, for example, where starch and softener may widely vary and will be greaseproofness is desired in connection with, for dictated by the particular characteristics desired example, carton board, a lacquer in nitrocellu- 55 lose and proportionally also in a plasticizer, say

66% nitrocellulose, of low viscosity, say of a viscosity of about (Hercules), and 34% plasticizer, will be desirable. Again where a high gloss is desired, the lacquer will be high in resin content, say resin 60%, nitrocellulose 25% and plasticizer The lacquer may include any suitable solvent mixture, though it desirably will be of such a character that residual odor will be readily eliminated, as, for example, a solvent mixture containing 0- methyl ether of glycol, 5-10% acetone and 95-65% ethyl alcohol.

It will be appreciated that the lacquer for application over the size or undercoat for theproduction of a lacquered surface or article, in accordance with this invention, may be of any known type suitable. or previously used for the purpose for which the lacquered material is intended.

In preparing a lacquered material, as, for example, a carton board, or an article fabricated therefrom, the starch undercoat is applied to the carton board and, after-the undercoat has dried, the lacquer is applied in any desired manner, as by spraying or brushing.

The term paper is used in the claims hereinafter set forth as inclusive of pasteboard, cardboard, cartonboard, and other composite paper 3. A waterproof, greaseproof and odorless packaging material comprising paper having a surface thereof coated with a film including starch and glycerol and having a nitrocellulose coating superimposed on said starch coating.

4. A waterproof, greaseproof and odorless packaging material comprising paper having a surface thereof coated with a film including starch and sulphonated castor oil and having a nitrocellulose coating superimposed on saidstarch coating. v

5. A waterproof, greaseproof and odorless packaging material comprising paper having a surface thereof coated with a film including starch and a softener therefor and having a coating including nitrocellulose and a plasticizer superimposed on said starch coating.

6. A waterproof, greaseproof and odorless packaging material comprising paper having a surface thereof coated with a film including starch and a softener therefor and having a coating including nitrocellulose, a resin and a plasticizer superimposed on said starch coating.

7. A waterproof, greaseproof 4 and odorless packaging material comprising paper having a surface thereof coated with a starch film deposited from a composition consisting of starch 2-25%, a softener for the starch 05-20% and water -9'7.5%, and a nitrocellulose coating superimposed on said starch coating.

8. A waterproof, greaseproof and odorless packaging material comprising paper having a surface thereof coated with a starch film consisting of about starch and about 25% glycerol, and a nitrocellulose coating superimposed on said starch coating.

9. A waterproof, greaseproof and odorless packaging material comprising paper having a surface thereof coated with a starch film consisting of about 71% starch and about 29% sulfonated castor oil, and a nitrocellulose coating superimposed on said starch coating.

WALTER D. BOWLBY. 

